Cleaning your brew kit – The practical chemistry behind effective soil removal

Posted on May 10, 2022 by westonfront

I still remember the advice given to me by my first head brewer. “The two most important aspects of brewing” he said, “are cleanliness and temperature control.”

There are three classes of soiling you need to deal with in a brewery:

Organic soiling – that could be burnt on carbohydrates / proteins on the hot side and yeast residues in your fermenter
Inorganic soiling – this would be mostly scale (calcium / magnesium oxide) or calcium oxalate.
Biofilms – these tend to form in places where liquor can lie and which don’t see turbulent flow. Under the plates in the mash tun and in wort transfer lines for example.

Organic soiling

The most frequent / routine soiling you’ll be dealing with is organic soiling in the copper and your fermenters. You want to free this off of the vessel walls and then ensure it remains suspended until you can flush it out. The best cleaning agent for organic soils is specially formulated caustic (NaOH) solution. Brewery caustic formulations come with surface active agents in them to improve wetting, sequest metal ions and keen non water soluble soils suspended.

Your CIP caustic solution should be 1-3% NaOH (normally the concentrate is 30% NaOH). Take care with the concentrate and follow your local risk assessment. Googles and gloves are required and always add caustic to water, not water to caustic to avoid it overheating and spitting.

If you are a micro brewery you will not use huge volumes of caustic and it’s worth being aware that you can usually buy something suitable from your local agricultural merchants as it is also used to clean dairy milk tanks. Take care though as dairies tend to prefer formulations that also contain hypochlorite. Evans Vanodine CIP liquid would be a good choice because it contains no chlorine based chemicals.

Different places where I have worked have had different protocols for the cleaning, but be aware that caustic cleaning is most effective at 50-80 C, needs to be recirculated for 15-20 min and should impact on your surfaces at > 1 m/s to guarantee turbulent flow. Why is there an upper limit you may wonder? That is to avoid baking your solids onto the heated surfaces. Here it’s worth mentioning the Sinner diagram:

You need all these factors to clean equipment, and if you reduce one (say chemical strength) you will need to increase one or more of the others (time, temperature or mechanical action). Once your vessel is free of soil you need to flush the caustic out as you definitely don’t want caustic in your beer. Simple phenolphthalein test papers work well to check the flush water.

With the base of your mash tun (below the plates) it is likely that you’ll not be able to use a spray ball system so you are probably looking at more mechanical action. Jumping into the vessel with a bucket and scourer or using a pressure washer! However this will probably only be necessary 2-4 times a year. This is a vessel entry, so again follow your local risk assessment. Actions should include, locking off any mechanical, chemical or heat inputs that you have and ventilating well.

Often a cold caustic cycle is all that is needed on the fermenter.

Cleaning fermenters – a cautionary tale

After you have transferred the beer from your fermenter there will be a high level of carbon dioxide with it. If you don’t already know, be aware that carbon dioxide reacts with caustic:

CO₂_(g)+ 2 NaOH_(aq) → Na₂CO₃_(aq) + H₂O_(l)

All of your CO₂ gas will become a dissolved solid, result – a big drop in pressure. It is readily possible to collapse an FV because of the vacuum formed. The safe approach to manage this issue will depend on the size of the fermenter. Massive lager FV’s would need an air purge and CO₂ monitoring. Smaller vessels can be managed by three x 10 second water sprays and leaving an inlet open during the initial caustic circulation. This worked fine on 5000 L FV’s with a 1 ½” being left open (and a short hose running to the drain). I have seen people leave the manways cracked open but this is dangerous in its own right as you’ll get hot caustic splashing into the work space – no thank you!

Inorganic soiling

In a small brewery you are most likely to see this in your hot liquor tank or in your casks. Here the aim is to solubilise the Ca / Mg salts with a suitable acid. The preferred option being phosphoric acid or a phosphoric / nitric mixture (NiPac B). This should be used at 1-4% and cold or warm, never above 50 C or it will fume. Again you’ll need a good water flush (see below) afterwards and this time litmus paper to check.

Biofilms

A less frequent task. If these are to be removed with CIP you would use your normal caustic solution (1-3%) but add to it some hydrogen peroxide (0.1-0.2%). However these often tend to build up in pipes where the flow rate is slow – such as the drain lines from your mash / lauter tun. Here the answer is mechanical effort! Sadly Murphy’s don’t sell elbow grease… I’ve had great success with a technique I used in the chemical industry called pigging. This is where an abrasive coated foam ‘pig’ is pushed down a line with air or liquid pressure. In the brew house a lower tech solution is required. Tie a foam scouring pad to a rope and pull through your lines until visual inspection shows them to be clean. The beauty, if there is one, with biofilm is that you can easily see it.

Sanitisation

Here there are a number of options, but a really good one is dilute peracetic acid. If used at 100-200 ppm it is not only an effective bactericide but will not need to be rinsed out of the vessel, simply drained. Another tip I learned is that most people can smell a dilute peracetic acid solution when it is above 75 ppm. So if you cannot smell it, either you have COVID or your solution is now too weak. Peracetic acid is another chemical you can buy readily from your local agricultural agent but again is something to be treated with respect as a concentrate and in accordance with your local risk assessment.

Flushing

Flush before you wash – that way the bulk of the soiling will be washed out and the potency of your cleaning chemicals will be preserved for multiple cycles.

Flush after you wash – Here you can work smart and save both time and water. Three ten second flushes will be a lot more effective than one 1-2 minute continuous spray down. The reason is all down to dilution (diluting by 90% three times (99.9%) is much better than diluting by 98% once). The pooling of liquor at the bottom of the vessel.

Need more advice?

If you buy your cleaning chemicals from a large supplier they are normally very happy to come and answer any of your questions. If you are a micro-brewery and this is not an option for you then contact me and I can help. Having worked in the chemical industry before I started brewing means I have a sound background in chemical safety and vessel cleaning methods.

Advanced Home Brewing Course – Theory & Practice

Posted on May 5, 2022 by westonfront

Would you like to take your home brewing to the next level?
Would you like 1:1 coaching from a professional brewer?
Would you like to have a professionally designed beer recipe, complete with water chemistry for your local water of a style of your choosing?

Earlier in the year a former colleague from my previous career (Chemical Industry) approached me and asked if I could shadow him on a brew day to help improve his understanding and technique. He had not been wholly satisfied with the beer he had made to that point and wanted to take his brewing to the next level.

I suggested the following, that we spend half a day covering the essentials of brewing science and looking over his brewing set up, then the next day he could brew with advice and input from myself on the best practice methods to use. For the brew day I had written him a recipe to clone his favourite commercial beer.

We both really enjoyed the two days. He said afterwards:

I wanted to improve my skills as a home-brew hobbyist and found so much conflicting and sometimes confusing information online that I didn’t know which way to turn to improve the quality of my beer which I felt had plateaued and at best was average. I also bought a number of brewing books which although a number were very good the time taken to reach mediocrity has been a good couple of years. Having invested several hundred pounds in equipment over this period I decided to reach out to The Hop Doctor to arrange a 1:1 session.The two sessions were fantastic

As well as brewing at commercial scale I also brew at home, but my approach is unusual. Brewing is my second career, and I have taken what I learned at commercial scale and through my IBD professional training and scaled it down to the 23 litre scale. Whilst the internet can be a great resource, there is a great deal of inconsistent and incorrect advice out there. I can bust those myths for you and explain the process based on the latest proven scientific understanding as gained from my IBD Brewing Diploma, commercial experience and my background as a Ph.D chemist.

Advanced Home Brewing – Theory & Practice

Half day of theory (with course notes to keep)
Shadowed Brew Day with professional advice and Q&A session

Cost: £235 for any location within 40 miles of the BB7 postcode

Other locations considered, travel costs at 75p / mile

Professional recipe design (for home use)

Recipe for 5 gallon system plus one recipe iteration (based on your thoughts on the first brew) within 3 months of initial recipe provision.

Cost: £45 (only as an addition to the above)

Spend a day with The Hop Doctor!

Thanks to Will for sharing his amazing level of professional knowledge which would have truly taken me years to learn. I’d highly recommend anyone from novice to intermediate home-brew hobbyist to contact him as I feel the small investment in myself was, is and will be enjoyed for years to come.

Which hop oils survive from the hot side – some recent research from Yakima Chief

Posted on April 18, 2022 by westonfront

My last post on hop addition timing attracted a lot of interest and someone from Yakima Chief reached out to me with a technical data-sheet which they published in 2021. I’ve shown the key chart below which quantifies the nature and level of hop flavour oils which they have detected in a finished beer vs. species and addition time.

hop-pellets

They don’t specify their methodology but compare a set of hop species whose oil content has the combination of concentration and properties (solubility, boiling point etc) which helps them to remain in the beer from the hot side and those whose qualities mean they are best added as a dry hop.

Species	Flavour / Comment*
2-Nonanone	Cheesy / Herbal
Geraniol	Floral
Linalool	Citrus / Fruity
2-Methylbutyl isobutyrate	Fruity / Apricot
Methyl Geranate	Floral
Isoamyl isobutyrate	Apricot / Banana
3-Mercaptohexanol	Tropical / Grapefruit

* A flavour combination is often different from the sum of it’s parts.

Information of hop oil composition is hard to find, so whilst the chart is only qualitative and only covers US varieties it does give a good guide to a range of 20 popular aroma hops. I know that one use I will be able to put this to is to combine hops with different oil profiles to better maximise the breadth of flavour experience in my beers.

A copy of the full data-sheet can be downloaded from here or here. If you are a micro-brewery wanting help with a beer design, please do get in touch and let’s see how I might help.

Towards a theory to explain the best time for hop additions

Posted on April 4, 2022 by westonfront

Is it possible to rationalise the best time to add specific hops into the wort boil? Not simply to maximise their bittering potential (that’s simple), but to extract and retain their flavour potential. This is the question I asked myself. Brewing is my second career, I started my working life as a problem solving chemist underpinned by a Ph.D in chemical mechanisms. Thus it has always been useful to me to understand the reasoning behind how a process is run. The why behind the what. So whilst it’s clear that late addition hops will lose less of their essential oils to evaporation, would it be possible to come up with an overall theoretical basis for which any hop flavour is best obtained at specific times within the boil? (not just the trendy ones.) I think the answer is yes.

I’ll not squander your time on the ideas that didn’t work and cut to the chase. When I drew up a list of all the essential oils which I could name if was clear that different flavour classes fell into different chemical functional group classes. i.e. All woody and spices flavour oils are higher molecular weight (MW) hydrocarbons or oxidation products of these. Citrus flavours come from low molecular weight (C₁₀) unsaturated terpenes / terpene alcohols and so on. Here is my list of those chemical classes:

Aroma / Flavour	Chemical class
Spicy / Herbal	Oxidation product (high MW)
Woody	Oxidation product (high MW)
Purely spicy	Oxidation product (low MW)
Passion Fruit	Thiol
Tropical Fruit	Thiol
Citrus	Unsaturated oxygenate
Floral	Unsaturated oxygenate or Biotransformate
Pine	Terpene
Resinous	Terpene
Grassy	Aldehyde (low MW)

If you then list the oils by boiling point, the rationale behind their use starts to becomes clear.

So what do we learn?

Hop derived traditional British beer flavours can survive from the first wort hop additions because of their high boiling point.
In general spicy herbal flavours are likely to require a reasonable length of time in the boil to facilitate their oxidation to epoxides, probably at least 20 minutes.
Experience suggests that oils with a boiling point below 230 C are readily lost and should be added at the whirlpool.(1)
Flavours from biotransformation are best achieved by dry hopping or whirlpool additions.
Add to the above knowledge the very low concentration of thiols present in hops and you can see that tropical flavours are only likely to be obvious from whirlpool or dry hop additions.

On these basis we can rationally add hops into the wort at the point which will maximise the flavour component we are seeking. So take Perle hops for example, which can offer both spicy and orange flavours. The spicy flavours would be best gained by adding in the flavour section to (+20 / +30 min) to allow time for oxidation. However, if we want the pine / orange flavours from this hop then this would be best achieved at the whirlpool. Observations such as this explain why the addition of the same hop at different stages of the boil can give a greater breadth of flavour to the beer. The same is true with dry hopping where additions during active fermentation should be expected to yield more biotransformation flavours that those added during warm conditioning. Thus a rationale for double dry hopping, but only if the correct hop varieties are used (those containing Geraniol / Linalool). Although I still suspect that the DDH moniker is more of a marketing term than a zymological one.

What I’d like to do next is to tabulate the flavour threshold of all of these oils to see what extra insight this sheds into the area. Highly experienced brewers are likely to have come to the above conclusions simply through their breadth of experience, but I know I’ve found it satisfying to bring some rational (ab initio) light to shine on this question.

I would really love to hear your constructive feedback on these ideas.

(1) 85% of hop oils added at the start of a wort boil are lost during the boil – F.R. Sharpe & D.R.J. Laws, J. Inst, Brew, 1981, vol 87, 96-107.

Acknowledgements: My thanks to Will Rodgers at Charles Faram and Thomas Shellhammer at Orgegon State University for helpful discussions

The importance of pH control in brewing

Posted on March 15, 2022 by westonfront

All through the brewing process, having your mash liquor, wort and proto-beer within the desired pH window is critical to both quality and yield. When we are mashing or fermenting we are relying on enzymes which work best within a tight pH window. During boiling it is chemistry rather than biochemistry which is at play, but still pH is critical to the final beer quality.

The chart below shows the ideal pH window as it tracks through the whole brewing process.

Mashing

During the mash we want the α and β amylases to work as effectively as possible and that means that the mash should be between pH 5.2 and 5.4. This is controlled primarily by your water chemistry which I covered in an earlier post. If your pH is too low your starch conversion efficiency will drop, if it’s too high you’ll start to extract tannins and silicates which you want to leave behind in the spent grain. If you are running a new recipe it’s wise to check this pH on the first couple of runs to make sure it within range. This is doubly important with darker beers, where the roasted malts can have a big impact on the pH. There are ways to estimate this, but they are only estimates and it’s best to check what you’ve achieved and adjust your calcium or bicarb addition levels on porters and stouts. After that it’s good to check your run off pH once a week / fortnight to check nothing has drifted.

That astringency that you taste in some stouts, it shouldn’t be there! That is someone not properly attending to their mash pH.

Mashing is the stage where pH is most critical, if you get inside the correct window here then it should track within the desired window for the rest of the process for beers above 3.0% ABV.

Sparging

Here you should be using either pH or SG to monitor your last runnings so as not to go too far. That last portion of weak worts doesn’t contain a whole lot of sugar but will contain undesirable levels of polyphenols or lipids if you let the pH go above 5.8 or SG below 1.006. Remember you are sparging with water which will be pH 7 or slightly above, so the pH of the run off will start to rise from the middle of the sparge onwards

Boiling

There’s a lot that goes on in the boil. The pH will impact the colour development, hop α-acid isomerisation and protein drop out (thus final haze stability). Different pH’s are ideal for each, so the key here is consistency. The pH drops during the boil due to the acid end products of the Maillard reaction and more Ca phosphate precipitation. If necessary you can add a little phosphoric or lactic acid during the boil if the pH is outside of your normal range. However if you have got your mash pH correct and not over-sparged you shouldn’t have an issue. If you are making a low alcohol beer you are likely to need to add a little acid to drop the pH into range.

Fermentation

Again we are trying to keep the enzymes happy and so long as we’ve done everything right up to this point all should be well. Yeast produces acids as a by-product of cell growth and also as one of it’s sugar transport mechanisms. One key thing to remember is to drop the yeast, or transfer the beer off the yeast in a timely fashion or you’ll see your pH rise, reducing shelf life as well as adding undesired ‘beefy’ flavours to your beer. If you are making a low alcohol beer again extra care should be taken and the pH adjusted if necessary.

pH measurement

After spending 20 years in the chemical industry I know more than a little about temperamental pH meters. If you are going to buy a pH meter don’t skimp on price or pick the cheapest one you can find on Amazon. These will never be as accurate or repeatable as you’ll need for brewing. Something from Myron or a bench based model from Jenway would be good options. If you cannot spend £250 then your better option would be to get some narrow range pH test sticks (try these or these). These may not be as precise but if you want something inexpensive yet accurate they are your very best option. You can know for sure if you are sitting inside your desired range or when to stop your sparge. They are quick too.

Malts with Superpowers…

Posted on February 21, 2022 by westonfront

The current craft beer scene has it’s focus on hops, these are the celebrities of today’s beer. But behind every great hop there has to be a great malt base!

A great beer is more than just aroma. The first thing that a customer assesses about a beer is it’s appearance and that is shaped by the malt bill. Whether you are looking for clarity or murky haziness, a brim full glass or a deep long lasting head these aspects come from the malt (and/or adjuncts) which form the grist. The range of malts available to us today is a veritable kaleidoscope

PureMalt Flavour Wheel

There is such a breadth of flavour options there, but the topic for this post are the less obvious characteristics which we can use to impact the more subtle but equally important aspects of our beer design.

Clarity or Haze…

The current trend in the UK is for hazy IPA’s. Permanent haze in beer comes mainly from protein-polyphenol complexes or beta-glucan and related polysaccharides. But you need the right protein, not just any protein. Here you should be looking at malted wheat. Torrified wheat has a high haze potential, but being ‘less-modified’ the protein fraction is of a larger molecular weight which tends to drop out with time. To further aid the haze and to give that ‘pillowy softness’ then use some malted oats which contribute beta-glucan / polysaccharides to achieve these effects. Don’t go crazy with the amount you use however as the lack of husk on the wheat or the beta-glucans in the oats could make for a very slow run off from your mash tun.

What if your aim is a beer of the ultimate clarity? This is probably best achieved by good water chemistry, careful optimisation of your boil time, kettle and auxiliary finings. But if you are working at the micro scale then finings optimisation trials are not always an easy option. Did you know that the major source of the polyphenols behind haze is the base malt, not the hops? Crisp offer a malt which they call ‘Clear Choice’ which is malted from a unique variety of barley which is free from the class of polyphenols which help form haze complexes. For an easy option at the small scale this could be something to consider.

Body

One of my earlier posts covers the various ways you can control the body of your beer. There’s no point repeating all that here just head to my post on bodybuilding. Suffice it to say that wheat and oats are again good choices, and if you are making a Stout consider some Munich malt which adds both body and some lovely complexity to the malt base.

Colour

Clearly the range of differently roasted malts offer a full palate of colour options for your beer. But what if you want to add the colour without the flavour? Here I’m thinking about something like a Red Ale or a Black IPA. Here Black Malt is your friend, but don’t add it to the mash, spread it over the top of the mash bed just before you start sparging – in this way you get a lot of the colour and very little of the flavour extracted.

Another related trick is needed if you want to make a lager that looks and tastes like it has been made via the traditional decoction method, but when you don’t have the kit or the patience to use this approach. The boil stage of decoction promotes the Maillard reaction yielding melanoidins. A similar effect can be achieved used a small proportion (2%) of Melanoidin malt within your malt bill. Here the melanoidins have been formed during the roasting process

Finally, if you want to get the colour and flavour from a roasted malt without the astringency then consider some dehusked malt such as one of the Carafa Special grades from Weyermann or Blackprinz from Breiss. Many of the polyphenols in barley is within the husk, if it’s not there it cannot impart the astringency. Also important with a stout is to get your pH right by adding some bicarbonate to a Stout Grist to keep the pH up to around 5.4. Dark roasted malts, rich in acidic melanoidins will reduce the pH in the mash and reduce your extract efficiency unless you correct for this.

Sweetness

Crystal / Cara malts are made via a different process to regular malts. Rather than being drying directly after malting, they are heated to a comparable temperature in a sealed drum so that they are ‘stewed’ before drying and roasting. This starts the saccharification process and the sugars become caramelised during the drying / roasting stages. A whole range of colour options exist. The most crushable hoppy beers of today have a backdrop of subtle sweetness to bring out the best of the fruity flavours from the hop oils. Pale Cara malts (15-25 EBC) are used to achieve this. Hops might seem to win all the Oscars, but Cara malt should win a gong for the Best Supporting Role.

For malt forward beers where sweetness is also important, some of the darker Crystal malts come into their own. These give toffee (Crystal Pale / 150) or caramel and dried fruit (Dark Crystal / 400) flavours to both traditional and modern porters and stouts. What did you think put the popcorn into Northern Monkey’s Film Club?

In everything, moderation

Finally don’t forget the most important superpower of all, and that is the enzymic power within base malts which turns the starch into sugars – the source of our alcohol. Enzymes are delicate and high temperatures denature them. Both roasted and crystal malts no longer contain functional enzymes so have no diastatic power. Thus when using these malts never use more than 10% of each and always have at least 70% of base malt within the grist. The two exceptions here are Vienna and Munich malts which retain enough diastatic power to be used at up to 100% of the malt bill, so these can be counted towards your 70% too.

More help?

Would you like a beer recipe designed for you, and even made at pilot scale for you to try? I can offer both of these services and very soon I will have the AWRS licence required for you to test out your new brew on your own customers for their feedback because launching into a full scale batch. If either of these are of interest, just give me a call.

Malt colour-gradient

10 days in the life of a locum micro-brewer…

Posted on February 14, 2022 by westonfront

There is a rather nice rural pub near to me that I know has its own 4 BBL brew kit. A chat with the GM in the autumn revealed that the kit hadn’t been run for quite a while because of the lack of an available brewer. When I conceived the idea of becoming a freelance locum brewer and beer designer this is one of the people I contacted to find if they wanted me come a breath life back into their nano brewery. They did, any they were not the only potential client…

Roll on a few months and I’d had some really fruitful conversations with the landlord and he was keen for his in-house ale to be made once again, traditional flavours in a golden beer. As with all my contracts I like where possible to start with a couple of hours of familiarisation with the last person to have run the kit. Whilst the unit operations of making beer on any small brew kit are almost identical, the foibles of each kit are often unique.

Having learned during my familiarisation session that this brew kit had not been run since 2018, I proposed that I should spend time recommissioning it. It had been left good and clean, but the last thing you want on your brew day is to find a leak, a faulty heating element or a pump that doesn’t work. Those things might be impossible to fix ‘on the hoof’. In this case I found two pumps which had seized due to swollen pump case seals. At this point, I need to say thanks to Dave at PBC who talked me through a simple fix which worked a treat.

Next on the list was to check the recipe which had been presented to me. There are a few design calculations that need to be correct for a beer to come out as you hope. As much fun as it is having a happy accident, getting the raw materials levels wrong on a brew is more likely to lead to something bland or unpleasant that a paradigm shift in craft beer design! All was good, so I recommended some suppliers and helped the landlord with the raw material order. That was a Friday, the following Thursday was brew day.

leaf hops

As the eagle eyed will have spotted the brew kit was a PBC / “Dave Porter” kit. Whilst their entry level kits are rather basic, I’ve been extremely pleased with the performance which I have coaxed out of the two that which I now regularly operate. The level of control is limited when compared to the 30 BBL which I used to run at Bowland but with some forethought it’s not hard to get excellent and consistent results. One of my tricks is to mash-in ‘in three thirds’. This allows me to quickly and easily make any corrections to my calculated strike temperature and allows me to use a single HLT set point for both mashing and sparging. My mash temperatures are always within +/- 0.5 C of plan, a performance equal to the use of pre-masher on a much larger kit. Extraction yields have always been around 99% too, so nothing to complain about there either.

Valentine Arm - Coach & Horses When it came to running off the wort I had a new toy to play with. This was a first time I’d seen a Valentine Arm in the flesh, but what a nice addition it was. The subtly by which I could adjust the flow rate of wort out into the under back was fabulous. It was so much better that the ubiquitous butterfly valve you find on almost all mash tun outlets.

Now I have wort coming up to the boil in the copper and it gives me a chance to pass on another tip for getting the best out of a small brew kit. As with any vessel you want to boil in, the working capacity is only ever around 80% of the total capacity. However, even with this precaution in place it is so much easier to boil-over a 500 L rather than a 5000 L copper. But one thing you can do is to take advantage of a little discussed feature of hops, that the lipids within them act as a natural anti-foam. Even if your beer design is aiming to add most of the hops at flameout, if you add just 5% of the bittering potential up front you can greatly minimise the foam formed by the initial protein precipitation of the boil making it easier to control the initial boil at a maximised capacity.

The rest of the day proceeded to plan and by the next morning there was pleasing krausen on top of the fermenter so I just needed to leave the yeast to do its job. In my experience, fermentation is slower in flat bottomed FV’s than cylindroconicals. Given that dry hop extraction is also better in the latter, I can only assume this is down to better mixing.

Racking off beer - Coach & Horses Five days later we were at 1010 and it was time for a diacetyl test. I find any beers which contain chocolate malt or Crystal 150 need a diacetyl rest and this beer was no different. Another two days and all was well and it was time to charge the auxiliary finings and cool. That brought me to the weekend, so I racked out on the Monday. And a week after that, my client was able to serve his own ‘in house’ beer after a gap of four years. Depending on how quickly it sells I can see there is scope to increase the batch size next time, but clearly this needs to be a good match for what can be sold over the eight weeks post racking. More exciting still is their enthusiasm for me to work with them on a new beer design, something pale and tasty for the summer months.

What a satisfying fortnight that was. It is always great to be able to work in an enthusiasm small team and to know that I can make a significant contribution to projects such as this, bringing a breadth of brewing experience, process plant understanding and IBD technical knowledge to bear. That’s why I love micro-brewing. Do you want to install a brew kit into your pub but don’t know how you would staff something that isn’t planned to run every week of the month? Would you like someone to check over a beer design or help you with your water chemistry? Just give me a call and let’s explore how I might help.

How to perform a diacetyl test – and why you should.

Posted on February 1, 2022 by westonfront

What is diacetyl?

For yeast cells to grow they need nutrients, some for energy and some to build new cell material to enable multiplication. That which they cannot draw from the wort, the yeast needs to synthesise from simpler starting materials. During the synthesis of the amino acid valine, a by-product is diacetyl.

The challenge with diacetyl is that it has a low taste threshold and it tastes of butterscotch, not a flavour we want in most beers.

How is diacetyl formed?

It is good to understand this, as it underpins how the diacetyl test works. As with most biochemical pathways, the formation of diacetyl is a multi-stage process. It is important to understand that up until the penultimate stage these steps are enzyme catalysed (i.e. fast) but the final step from α-acetolactate (AAL) to diacetyl is a simple but slow chemical reaction. With AAL being capable of being formed faster than it is consumed, a residual concentration can build up in the final stages of fermentation. This is especially true in lower temperature fermentations. Thus once your ale / lager has reached its terminal gravity it may not taste of diacetyl, but if AAL is present, it will be formed with time in the final package. Thankfully yeast also contains an enzyme which will reduce diacetyl to 2,3-butandiol which has a far higher taste threshold and this eliminates the off flavour issue. Thus the diacetyl rest, a period of warm conditioning at the end of fermentation, which allows the AAL to convert to diacetyl and under conditions where it can be consumed to form something essentially flavourless. Cool down the green beer and this enzyme cannot act.

So what is a diacetyl test and how to I perform it?

You could take a sample of your green beer and inject it into an HPLC and see if AAL is still present, but if you don’t have a spare £25k burning a hole in your pocket there is a far simpler and cheaper method:

Take two samples of your green beer, 50 ml each is enough, into sealed bottles. Place one into the fridge (the control) and drop the other into a jug of hot water at 60-70 C, chances are you have some hot liquor to hand which would be ideal for this. Leave the sample in the hot water for 20 min then remove and cool. Then all you need to do is to taste both samples.

Can you taste butterscotch in the heated sample (having the control sample to compare against makes this assessment much easier) – If you can then you have some AAL still present in your green beer which will form diacetyl with time. The green beer needs longer to warm condition so hold at 16-20 C for another 24-48 hours and then run the test again.
There is no diacetyl taste to either sample – your beer is ready to chill and move forwards.

My experience

Residual AAL / diacetyl is present at the end of the primary fermentation of some recipes but not all. The key factors are the choice of yeast, malt bill and fermentation temperature. Some combinations will require a diacetyl rest, some will not. Some craft breweries are paranoid about diacetyl in their beer and warm condition all their batches, but unless you are making a lager, this is an unnecessary loss of brewery efficiency. When you are running a new recipe then run the test for the first three gyles. If the test comes out negative at the end of each primary fermentation then unless you change anything it always will. Carry out warm maturation only on the beers which need it. Beer design is, in part, an art but its manufacture is certainly a science.

If you find yourself with a beer design where AAL / diacetyl is present at the end of the primary fermentation you do have another option. That is to add an exogenous enzyme (AAL decarboxylase / ALDC ) into your FV at the start of fermentation to guarantee that all the AAL will be quickly reduced to acetoin and no diacetyl will ever be formed.

Would you like help with the consistency of your beer quality? If so give me a call and we could arrange a phone / video consultation or if you are local I could come out and help you in person.

Body building – tuning the mouth feel of a beer by design.

Posted on January 19, 2022 by westonfront

The body of a beer makes a big difference to the drinking experience. The amount of body that you target depends on both the style and the drinking audience you are aiming for, but for an excellent beer it needs to fit the style. The beauty of the brewing process is that there are a very wide range of variables you can play with to adjust the body of your beer.

There is a view, to which I also subscribe, that the ideal craft beer will taste as if it is 5% ABV. That means that our beer design may be seeking to increase the body of a low ABV example but reduce the body in an imperial stout. It’s like going to the gym, some people are there to increase their tone and muscle bulk, others are looking to shed a few pounds.

What is body?

This is the first thing to understand, because when you, the rationale behind the process variables that influence it become clear. Predominantly the body of a beer (or any beverage) is related to the viscosity. Viscosity, for those who are interested, is the resistance to flow within a liquid. Think of water at one end of the range and honey at the other. Other key factors that influence how we perceive the body of a beer are the sulphate:chloride ratio and the level of carbonation. These factors are important but are secondary to the viscosity.

So what influences the viscosity of beer?

Simple, the higher the amount of dissolved solids and the higher the molecular weight of those solids the higher the viscosity of the beer. Considering a 4.4% European Pilsner for example; we would expect around 3% unfermented sugars and 0.3% protein to be the major dissolved solids. It is worth remembering that the molecular weight (MW) of the proteins present could easily be 10-20 times higher than the unfermented sugars, so their effect will be higher than their concentration seems to suggest.

INCREASING BODY

We could simply increase the ABV, because as this rises so does the total sugar content of the wort. Whilst the relative percentage of unfermentable sugars remains the same, their absolute level rises. Thus the higher body we generally experience in stronger beers.

But let’s say we are looking to make a session beer at 3.7% but we don’t want it to taste watery, what options do we have?

Careful choice of the malt bill
Add an adjunct that contains higher molecular weight proteins
Select the best mash temperature
Consider a step mash
Use a lower attenuation yeast
Use a lower sulphate:chloride ratio in your brewing salt addition/s.
Add lactose

Malt choice

This is one of the two most powerful tools you have open to you, the other being your choice of yeast. Crystal malts are commonly used to increase the body of a beer, their unique malting process leads to caramelised sugars being present in the malt itself. If you don’t want to also add strong flavours then choose a lightly kilned version – often called Cara malts, these will add a little sweetness but not the stronger caramel or dried fruit flavours of the darker crystal malts. Note that crystal / cara malts have a very low enzymic potential so should only be used at < 10% of the total malt bill. Another option is Munich malt but this has a higher flavour potential so is often best used in darker beers where it’s maltiness will be a welcome layer of flavour rather than a distraction.

Lower Attenuation Yeast

An alternative to putting more body in is to take less out! Lower attenuation yeasts such as Fermentis S-33 or Lallemand BRY-97 are more selective in the sugars they convert and thus leave more behind the final beer. If you use one of these you may want to do something counter-intuitive with your mash temperature so your final gravity is not too high and that is to mash in at a lower temperature (i.e. 65 C).

Adjuncts

It is common to add oats or wheat to increase the body of the beer. Be careful with the level you use though. Both adjuncts contain larger molecular weight proteins, some of which will be left, like a sludge, in your mash tun. High levels will also lead to a lack of haze stability, which can be a problem or an advantage depending on the style you are aiming for. Oats also add beta-glucans and other viscous polysaccharides to the beer, but if you add too many, the viscosity of your mash will rise and increase your sparge / run off times or may lead to a stuck mash. The lack of husk on malted wheat can also lead to similar problems albeit via a different route. If you are using as mash tun, then add your wheat to your grist hopper towards the end so the wheat does not sit directly above the plate.

If your brew kit allows for a step mash, then it is possible to extract more of the medium molecular weight proteins from these adjuncts by including a protein rest. This breaks down the problematic high MW proteins (less sludge) to form more of the ‘body building’ medium MW proteins which are wanting to move forwards in the process.

Mash temperature

A subtle change here can have a significant effect on your final beer. You have competing enzymes in your malt and at higher temperatures α-amylase wins out leading to a higher level of more complex, lower fermentability sugars and with this, more body.

Adjust your brewing salts

Higher relative levels of chloride in a beer are known to increase the perceived body. With something like a Stout you would want higher chloride levels anyway to bring out the lovely malt flavours. A less obvious example of this approach is with NEIPA’s. Whilst these beers have a very high hop level, the style demands a lower bitterness and also uses low colour malts so there is little or no malt character to be enhanced. NEIPA’s are commonly made with a 1:2 – 1:3 sulphate:chloride ratio.

Add Lactose

Finally, you could simply add a non fermentable sugar to build you body, an approach traditionally used with a Milk Stout. Lactose is a lot less sweet than sucrose but is sweet nonetheless, so be cautious in the amount you add if you take this route, start with something in the 3-7% range.

REDUCING BODY

If you are one of the mega brewers then one of your aims is to make a lager which is easy to drink, something with less body that you would expect for the ABV. This is one of the reasons why Budweiser is made with some rice within the malt bill. If you are reading this you are probably not seeking to make the next Bud Light, but the same principles apply. A beer whose body is too high is less satiable; it is something where a half might be enough. If you want to make a high ABV beer more session-able, what options do you have open to you?

Add an adjunct
Select the best mash temperature

Use a higher sulphate:chloride ratio in your brewing salt addition/s.

Add an adjunct

Mash adjunct

There is no shame in using some rice within your malt bill. But you need to use it in the right form and at the right level. It is necessary for all starch sources to gelatinise (hydrate and open up ready for the enzyme action) and is it really handy that malted barley does this between 61-65 C so this happens without you having to think about it. Rice however requires 70-80 C. Mega-breweries have a separate vessel for this step, but as a micro-brewer you can buy Flaked Torrified Rice which has been ‘pre-gelatinised’ and is ready to charge into your mash tun. Something else to note is that rice has no enzymic power and very low FAN (link to definition), so needs to be partnered with barley malt to enable saccharification and yeast health. Keep the level below 25%.

Kettle adjunct

Rice lowers body because it produces a much higher percentage of fermentable sugars than malted barley. Another approach to achieve this would be to add simple sugars directly into the copper. This is the approach used by the Belgians to make beers North of 10% ABV which do not feel like treacle. Sugar syrups, candy sugar and honey are all options. These are 100% fermentable so give you alcohol without the body.

Mash temperature

The opposite approach to body boosting applies here of course and that is to aim at a lower mash temperature to favour β-amylase and thus gain a higher proportion of fully fermentable maltose.

Adjust your brewing salts

Here your exact approach will depend on the style you are aiming for. You want to increase the sulphate:chloride ratio but the extent will depend on the style. For a malt forward beer you are likely to want to keep a modest excess of chloride – say 1:1.25 but for a double IPA you be be free to go for 3-4:1. Here you are looking for a subtle malt backbone at most and are likely to want the bitterness to balance well with what is likely to be a higher level of background sweetness.

Final comments

A commercial beer design needs to both good to drink and practical to manufacture. As you have now seen we have plenty of factors at our disposal. Which we choose to use will depend on the style being targetted and capability of the brew kit we have at our disposal. If you are want some guidance with beer design, or help with practical processing problems then please give me a call and we can arrange a phone/video consultation or, if you are based in the North West of England a site visit.

Understanding Water Chemistry

Posted on January 6, 2022 by westonfront

Understanding and controlling the water chemistry of your brewing liquor is essential to making excellent beer at high yields.

Step back 150 years and the reason why some water sources gave better beer at better yields was simply not understood. Certain cities became famous for the beers which worked out best with their water. Through a process of trial and error, brewers worked out which beer styles best suited the water they had available to them. London was noted for its’ Porter, Burton-on-Trent for pale hoppy beers (in those days meaning bitter rather than rich with hop oils), Dublin for Stout, Pilsen and Budweis for pale lagers and so on. In was only in 1850’s that a Dr Sheridan Muspratt speculated that the gypsum in Burton well water is what made it special. We had to wait until the early 20^th century before the full picture emerged and showed the importance of Calcium (Ca²⁺), Magnesium (Mg²⁺), carbonate (CO3^2-) sulphate (SO4^2-) and chloride (Cl^–) ions across multiple stages of the brewing process.

Some people think of water chemistry as too complicated and simply ignore it, but that approach means that both the brewer and the drinker miss out on a wide range of benefits from designing their brewing liquor composition correctly. So what are the main benefits?

The pH in the mash is critical* and this is influenced by the alkalinity of the water which is increased by carbonate, but reduced by Ca²⁺ and Mg²⁺ ions {via the precipitation of Ca / Mg phosphate salts resulting in the release of hydrogen ions (H⁺)}

*In the mash you are using the power of enzymes such as α and β amylase to break down the barley starch into sugars. Enzymes are very sensitive to their environment, they work best within tight pH, temperature and reagent concentration windows.

α-amylase is stabilised by calcium ions, and thus more long lived and effective when they are present at a sufficient concentration.
Together this means that you will get a better extract yield with the correct calcium concentration in your brewing liquor. Darker beers need more calcium to compensate for their lower enzyme level too.

Yeast health and flocculation is aided by calcium ions.

We now know that it is not simply sulphate, but the sulphate to chloride ratio which is important in beer. This impacts which aspects of the beer are most prominent to the palate of the drinker. They are perhaps best thought of as seasoning. A high sulphate:chloride ratio (say 3:1) will express the bitterness where as a low sulphate:chloride ratio (say 1:2) will bring out the malty flavours.

The great news is, now that we understand the impact of water chemistry, we should be able to brew excellent beers of almost any style anywhere in the world simply by adding or removing the desired ions from the water to meet our needs. So now know the most significant benefits, what are we going to control and how are we going to do it?

Step 1 – understand the composition of your incoming water.

The best option is to have your water analysed for its “mineral” (dissolved ionic salts) composition. If you are using spring or well water this will be your only option. If you are buying a significant amount of brewing products from Murphy’s & Sons they will happily analyse your incoming water once a year for free. If not they offer this as a paid service for around £30. A very worthwhile investment.

If you are using mains / municipal water, another option is to search for the website of your local water company, most of them publish the ‘average composition’ of the water they provide by postcode. Expect water from rainwater catchment to be low in Ca and other dissolved salts, but ground water to be rather higher because of the salts dissolved from the rocks it has passed through.

Look out for elevated levels of Fe (> 0.5 ppm), Cu ( > 0.5 ppm), Mn (> 0.1 ppm) or nitrate (> 10 ppm) in your water too. If they are above these levels they will cause you flavour issues from day one, reduce your shelf life and impact your yeast health. If present at elevated, you will need to install an ion exchange column or related technology to reduce their level/s.

Step 2 – decide your ideal calcium, sulphate and chloride levels for the beer style

Style	[Ca] / ppm	Alkalinity (as ppm CaCO₃)	[SO₄^2-]	[Cl^–]	SO₄:Cl
Pale lager	50-75	0-40	0-150	50-100	1:1
Pale Ale	50-100	0-80	50-150	50-100	2:1
Amber Ale	50-150	80-200	50-150	50-150	1:1
Stout	50-75	80-160	50-150	50-150	1:2

They are quoted as ranges because (i) you usually have to work within the constraints of your raw water, which will already contain some of these ions, and (ii) you may need also to reduce the alkalinity of the water by the addition of calcium sulphate / chloride (see step 3). In most cases it would be impossible to hit precise values for all these aspects; fortunately experience shows that it is not necessary to be that precise.

Step 3 – calculate the total and residual alkalinity of your water.

Look for the ‘total alkalinity’ TA value (quoted as ppm CaCO₃), Ca and Mg levels in your water report. From these you can calculate the residual alkalinity RA you would expect in your mash.

RA = TA – ([Ca in ppm] / 1.4) – ([Mg in ppm] / 1.7)

Using this equation, check whether, with your first approximation of your planned calcium level, whether your RA will fall into range. If not, will it come in range if you increase the Ca level to near the top of the desired window? If the answer is still no, which is likely to be the case if you are making a Stout with soft water for example, then you will need to add some sodium bicarbonate (NaHCO₃) to increase the alkalinity without changing the calcium level. Experimental studies show that for every 10 ppm you want to increase the TA (in ppm CaCO₃ equivalent) you need to add 17 ppm NaHCO₃.

Step 4 – calculate the ratio of CaSO₄ to CaCl₂ you need to use.

The calcium that you add can be in the form of the sulphate or the chloride. Brewing textbooks will take you into the unique realm of milli-equivalents. But since I was a chemist before I was a brewer I’d suggest it’s easier just to look at the mass of each anion (sulphate or chloride) you want to use and calculate how much calcium this contributes. If you build a simple spreadsheet based on the following compositions / assays of the brewing salts it is quick and simple to adjust the levels iteratively until you get both your SO4:Cl ratio and [Ca] into range.

Salt	[Metal ion] / % w/w	[Anion] / % w/w
CaCl₂.1.84H₂O^§	28.3	48.7
CaSO₄(gypsum)	29.5	70.5
MgCl₂.6H₂O^§	12.0	34.9
MgSO₄(Epsom salts)	12.0	47.2
NaCl	39.3	60.7

^§Commercially available chloride salts are hydrates, they contain a small amount of water chemically bound within the structure. 77% CaCl₂is the hydrate shown above. For simplicity in the main text I have not included the waters of crystallisation in the formulae.

I have included sodium chloride (NaCl) and the two magnesium (Mg) salts here too. If you have water which is already naturally high in calcium, it may not be possible to balance the SO4:Cl ratio without exceeding the desired total calcium level. In such cases you can add the required anion as the magnesium or sodium salt thus leaving the calcium level unchanged. Do note though that you should not exceed 100 ppm Na (starts to taste salty) or 15 ppm Mg (becomes a laxative!) if you do need to use these.

Worked example

We want to make a hop forward blonde ale…

Step 1 – find out the quality of the raw water

We get the following analysis back on the quality of our incoming mains water:

Component	Concentration
Alkalinity (TA)	140 ppm as CaCO₃
Ca	80 ppm
Mg	3.2 ppm
Na	10.6 ppm
SO4	120 ppm
Cl	23 ppm

Step 2 – decide the ideal water profile for what we are making

For a hop forward blonde ale we would ideally required:

Component	Concentration
Alkalinity (RA)	50-100 ppm as CaCO₃
Ca	50-100 ppm
SO4	50 -150 ppm
Cl	0-100 ppm
SO4:Cl	2:1

Since we want to make a hop forward style we will malt to suppress the malt flavours to showcase the hops so we would look for a high SO4:Cl ratio, let’s assume we aim for 2:1. Also let’s clarify here, this is the ratio of the weight of sulphate to the weight of chloride, it’s as simple as that (no reason to be thinking about moles or milli-equivalents)

Step 3 – Calculate the residual alkalinity (RA) at the desired [Ca]

The calcium level in our water is already within the desired range, so we would calculate the RA based on the raw water itself.

RA = TA – ([Ca in ppm] / 1.4) – ([Mg in ppm] / 1.7)

RA = 140 – (80 / 1.4) – (3.2 / 1.7)

RA = 79.7 ppm as CaCO₃

This too falls within our target range.

Step 4 – calculate the ratio of CaSO₄ to CaCl₂ you need to use.

The level of sulphate in our water is already high but the chloride low, the ratio of SO4:Cl being 5.2:1. Thus we are going to need to add a chloride salt to reduce this ratio. We have two options, we could add CaCl₂ to get our 2:1 ratio but the resultant [Ca] would then be 101 ppm and the new RA = 66 ppm as CaCO₃. The Ca level would be only just outside the desired range so that would probably be acceptable. Another option would be to add the chloride as NaCl which would leave the [Ca] and RA unchanged. Let us look at how we calculate this addition.

Desired [Cl] = 60 ppm

Current chloride conc. = 23 ppm

Need to increase [Cl] by 60 – 23 = 37 ppm

Using the table above we note that NaCl is 60.7% Cl so the additional [NaCl] required to achieve this is:

37 ppm / 60.7% = 61 ppm NaCl

Finally let’s check that this does not take the total [Na] above 100 ppm.

Na contribution from 61 ppm NaCl

= 61 x 39.3% Na

= 24.0 ppm Na

Total [Na] = contribution from raw water plus contribution from added NaCl

= 10.6 + 24.0 = 34.6 ppm.

So we have our answer, because we already have a gypsum rich water supply we need only add 24 ppm, or 24 mg per litre, of NaCl to get the ideal brewing liquor for our blonde ale.

If you would like more help with water chemistry, contact me and we can look at it together.

Hop Doctor

Locum Brewer & Micro Brewery Consultant

Category Archives: Brewing